/*  mbed Microcontroller Library
    Copyright (c) 2006-2013 ARM Limited

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
#ifndef MBED_FILEHANDLE_H
#define MBED_FILEHANDLE_H

typedef int FILEHANDLE;

#include <stdio.h>

#if defined(__ARMCC_VERSION) || defined(__ICCARM__)
    typedef int ssize_t;
    typedef long off_t;

#else
    #include <sys/types.h>
#endif

namespace mbed {

    /** An OO equivalent of the internal FILEHANDLE variable
        and associated _sys_* functions.

        FileHandle is an abstract class, needing at least sys_write and
        sys_read to be implmented for a simple interactive device.

        No one ever directly tals to/instanciates a FileHandle - it gets
        created by FileSystem, and wrapped up by stdio.
    */
    class FileHandle {

      public:
        /** Write the contents of a buffer to the file

            @param buffer the buffer to write from
            @param length the number of characters to write

            @returns
            The number of characters written (possibly 0) on success, -1 on error.
        */
        virtual ssize_t write(const void* buffer, size_t length) = 0;

        /** Close the file

            @returns
            Zero on success, -1 on error.
        */
        virtual int close() = 0;

        /** Function read
            Reads the contents of the file into a buffer

            @param buffer the buffer to read in to
            @param length the number of characters to read

            @returns
            The number of characters read (zero at end of file) on success, -1 on error.
        */
        virtual ssize_t read(void* buffer, size_t length) = 0;

        /** Check if the handle is for a interactive terminal device.
            If so, line buffered behaviour is used by default

            @returns
              1 if it is a terminal,
              0 otherwise
        */
        virtual int isatty() = 0;

        /** Move the file position to a given offset from a given location.

            @param offset The offset from whence to move to
            @param whence SEEK_SET for the start of the file, SEEK_CUR for the
             current file position, or SEEK_END for the end of the file.

            @returns
              new file position on success,
              -1 on failure or unsupported
        */
        virtual off_t lseek(off_t offset, int whence) = 0;

        /** Flush any buffers associated with the FileHandle, ensuring it
            is up to date on disk

            @returns
              0 on success or un-needed,
             -1 on error
        */
        virtual int fsync() = 0;

        virtual off_t flen() {
            /* remember our current position */
            off_t pos = lseek(0, SEEK_CUR);
            if (pos == -1) {
                return -1;
            }
            /* seek to the end to get the file length */
            off_t res = lseek(0, SEEK_END);
            /* return to our old position */
            lseek(pos, SEEK_SET);
            return res;
        }

        virtual ~FileHandle();
    };

} // namespace mbed

#endif
